I get a little snow in the drivers side of the engine bay on the F250 and it get's on my ballast and that is why my HID on the driver's side goes out allot, I will be replacing the ballast and finding a better spot to mount it maybe use some of that pond liner I have to make a cover. Did you spot any sing of snow on your balast or do you think it was just the cold, because I won't be too impressed if every time it get's a little extra chilly a light goes out....lol